Update RendererDecorator.php

The Decorator MUST implement the RenderableInterface contract.

Author: eugenedan

Diff for: Structural/Decorator/RendererDecorator.php

@@ -3,11 +3,11 @@
 namespace DesignPatterns\Structural\Decorator;
 
 /**
- * the Decorator MUST implement the RendererInterface contract, this is the key-feature
+ * the Decorator MUST implement the RenderableInterface contract, this is the key-feature
  * of this design pattern. If not, this is no longer a Decorator but just a dumb
  * wrapper.
  */
-abstract class RendererDecorator
+abstract class RendererDecorator implements RenderableInterface
 {
     /**
      * @var RenderableInterface